In class the following day nothing appeared to be different. No pair bonding, David thought cynically. They accepted being mated as casually as the cattle did. If there was any jealousy of the two fertile males, it was well hidden. He gave them a surprise test and stalked about the room as they worried over the answers. They would all pass, he knew; not only pass, but do exceptionally well. They had motivation. They were learning in their teens what he hadn't grasped in his twenties. There were no educational frills, no distractions. Work in the classroom, in the fields, in the kitchens, in the laboratories. They worked interchangeably, incessantly—the first really classless society. He pulled his thoughts back when he realized that they were finishing already. He had allowed an hour, and they were finishing in forty minutes; slightly longer for the Fives, who, after all, were two years younger than the Fours.

The two oldest Ds headed for the laboratory after class, and David followed them. They were talking earnestly until he drew near. He remained in the laboratory for fifteen minutes of silent work, then left. Outside the door he paused and once more could hear the murmur of quiet voices. Angrily he tramped down the hallway.

In Walt's office he raged, "Damn it, they're up to something! I can smell it."

Walt regarded him with a detached thoughtfulness. David felt helpless before him. There was nothing he could point to, nothing he could attach significance to, but there was a feeling, an instinct, that would not be quieted.

"All right," David said, almost in desperation. "Look at how they took the test results. Why aren't the boys jealous? Why aren't the girls making passes at the two available studs?"

Walt shook his head.

"I don't even know what they're doing in the lab anymore," David said. "And Harry has been relegated to caretaker for the livestock." He paced the room in frustration. "They're taking over."

"We knew they would one day," Walt reminded him gently.

"But there are only seventeen Fives. Eighteen Fours. Out of the lot they might get six or seven fertile ones. With a decreased life expectancy. With an increased chance of abnormality. Don't they know that?"

"David, relax. They know all that. They're living it. Believe me, they know." Walt stood up and put his arm about David's shoulders. "We've done it, David. We made it happen. Even if there are only three fertile girls now, they could have up to thirty babies, David. And the next generation will have more who will be fertile. We have done it, David. Let them carry it now if they want to."

By the end of summer two of the Four-strain girls were pregnant. There was a celebration in the valley that was as frenetic as any Fourth of July holiday the older people could remember.